Substance Use Disorders (SUD) and Alcohol Use Disorders (AUD) are among the most prevalent psychological disorders and represent the biggest single burden on health care costs in the United States. SUD and AUD have been found to be strongly associated with Borderline Personality Disorder (BPD) with the link between them unclear. This study explored a psychoanalytic approach to personality development that suggested that deficiencies in separation and individuation during toddlerhood and adolescence lead to maladaptive personality outcomes that can cause SUD and AUD. It was suggested that BPD would act as a mediator between the variables suggesting that deficiencies in separation-individuation lead to BPD and then SUD and AUD. This paper contributes to the understanding of these mental illnesses by reviewing the psychoanalytic literature about how these illnesses develop and providing statistical support for these ideas.

Participants in this study are 1275 ethnically and racially diverse adult outpatients between the ages of 18 and 63 undergoing psychotherapeutic treatment at the McShane Center for Psychological Services at Pace University's clinic in Downtown Manhattan. The Profile of Depression and Individuation (PADI) and the Personality Assessment Inventory (PAI) were administered to participants and mediation analyses were run to determine the relationships between eight scales of the PDI and eight scales from the PAI. The vast majority of the hypotheses tested were found to be significant lending empirical support to the psychoanalytic propositions that separation-individuation difficulties underlie psychopathology in general and more specifically, they are at the root of BPD, SUD and AUD. Support was also provided for the hypothesis that separation-individuation outcomes lead to BPD and then AUD and SUD. Limitations, implications, and directions for future research are discussed.